ML19347D308
| ML19347D308 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 10/03/1973 |
| From: | Ross D JERSEY CENTRAL POWER & LIGHT CO. |
| To: | Anthony Giambusso US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 8103120632 | |
| Download: ML19347D308 (2) | |
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Jersey Central Flofes & Light Company M ADISoN AVENUE AT PUNCH Bowl Ro AD e MoRRISToWN. N.J. 07960 e 539 6111 October 3,1973 X
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Q Mr. A. Giambusso
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Deputy Director for Reactor Projects 0
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Directorate of Licensing C
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United States Atomic Energy Commission
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Washington, D. C. 20545 R[Th
Dear Mr. Giambusso:
Subject:
Oyster Creek Station Docket No. 50-219 Differential Pressure Switch Failure The purpose of this letter is to report a failure of differential pressure switch DPS66A to trip and thereby actuate the reactor building to torus vacuum breaker block valves, V-26-16 and 18.
This event is considered to be an abnormal occurrence as defined in the Technical Specifications, paragraph 1.15.D.
Notification of this event as required by the Technical Specifications, paragraph 6.6.2.a., was made to AEC Region-I, Directorate of Regulatory Operations by tele-phone on September.!4,1973 and by telecopier on September 25, 1973.
While perfarming routine surveillance testing as required by the Tech-nical Specifications, paragraph 4.5.I.5., differential pressure switch DPS66A failed to trip. The cause for this failure was determined to be due to excess friction in the linkage pivots.
The switch was removed, disassembled and cleaned.
After reassembly and installation, the unit was satisfactorily trip-tested twenty times and returned to service.
Details of the switch are:
Manufacturer: Dwyer Model Number:
163512 llistory of Failures: No previous failures.
As noted in the Technical Specifications, "The absorption chamber-reactor building vacuum relief system assures that the primary containment is not operated at a negative pressure relative to its surroundings.
. The vacuum re-lief system is a redundant system and full capacity is available through either valve." Further, the differential pressure switches are themselves redundant in that either pressure switch will actuate both block valves.
In this case, since one of the switches was operable, full relief capacity would have been provided through 7d Q fl0/50hN
tw Mr. Giambusso October 3,1973 either valve since both would have been available. The significance of this event then is the loss of redundancy of the actuating switches.
The redundant differential pressure switch DPS66B will be disassembled and cleaned. No further action is planned at this time since this is believed to be an isolated occurrence based on four (4) years of satisfactory performance from these switches.
Enclosed are forty (40) copies of this report.
Very truly yours, v"?!
afY Donald A. Ross Manager, Nuclear Generating Stations DAR:cs Enclosures cc:
Mr. J. P. O'Reilly, Director Directorate of Regulatory Operations, Region I l
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